Contribution allocation for voltage stability in deregulated power systems

With deregulation of power systems, it is of great importance to know who contributes to avoid a voltage collapse, which could be due to different parts of the power system-generator, control system and transmission part, etc. This paper focuses on how to allocate the responsibility and contribution by bifurcation analysis. The authors investigate how parameters of the system influence the bifurcation points. Three bifurcations the singularity induced bifurcation, saddle-node and Hopf bifurcation, and their relationship to several commonly used controllers, are analyzed. Their parameters´ impact on the bifurcation points is investigated in this paper, from which the authors found a way to allocate the contribution by analyzing the relative positions of the bifurcations. They also analyzed the influence of other parameters (parameters of transmission and generators) on the bifurcation points. A simple two-bus system is used in this paper to demonstrate their approach. Their result shows that bifurcation analysis is a credible way to allocate the contribution, and the analysis will help design the controller and optimize the system to avoid voltage collapse.